Hazard was in excellent form again this weekend, bagging a hat-trick against Cardiff.
Former Napoli manager Sarri reckons the winger is up there with Lionel Messi and Cristiano Ronaldo as the best in the business.
Sarri also claims that Hazard, who has scored five goals already, could finish the season as Premier League top-scorer.
Collymore, however, says the 27-year-old Belgian international still has much to prove before he can be justifiably included in the top bracket of stars.
He told The Mirror: “Maurizio Sarri says Eden Hazard may be the best player in Europe right now, but not for me he isn’t.
“You’re still looking at Lionel Messi, Cristiano Ronaldo, Neymar and Antoine Griezmann – and I don’t think he’s there yet.
“Hazard has started the season well and, if he continues in the same vein, will be looking at a Ronaldo or Messi-esque goal haul of around 35, and I hope he can get there.
“But only then will I start to put him up with those players and not before.”
Former Chelsea ace Scott Minto has a differing view of the former Lille winger.
He’s convinced that Hazard has shown enough domestically and at the summer’s World Cup to be included in the Messi and Ronaldo debate.
Minto told Love Sport Radio: “I do think he’s capable of [of scoring 40 goals]. I really do.
“I covered Spanish football for four years and I saw Ronaldo and Messi, and the way they did it.
“He’s just below them. The only thing that has kept him below is perhaps the…
“I’ve not met him but I’ve heard about what he’s like as a person and a trainer. He’s a great lad, he’s one of the boys, he works hard.
“But I don’t think he quite realises how good he can be and what exactly you need to do to get every last ounce out of yourself to be the best.
“Him trying at 50 per cent is better than the rest of us could ever be, but him trying at 100 per cent and really believing he could get up to the Ronaldo and the Messi level.”